Growling/rumble and slippage ...

[PA Highlander]

The rig: '86 MJ, 2.5L, AX5 5 speed, NP207 t-case - 195,940 miles

The problem: growling/rumble noise most noticeable while coasting under power, also slippage under load (i.e. climbing a grade)


The noise sounded somewhat like a bad u-joint so today I replaced both u-joints in the rear shaft. The noise remains. There seems to be more rotational slop in the rear output of the NP207 than there is compared to my '95 XJ NP231. The slippage feels like an automatic tranny slipping. Now I've had two thoughts come to mind: 1) clutch very worn w/ pressure plate rattling 2) t-case, chain stretch slapping the housing and slipping under load. Thoughts and ideas for narrowing this down?

Thanks!

 

[8Mud]

The couple of loose chains (slipping) I´ve experienced, were pretty radical experiences. Sounded like a tin coffee can full of nuts and bolts shaken vigoursly and the drive train ratched/bucked, rather strongly.
The roar you are hearing, could likely be worn carrier bearings and/or worn spider gears, which will both roar pretty good when coasting and/or in reverse. So will a loose pinion or severly worn ring gear. I´ve changed quite a few sets of carrier bearings, they seem to be pretty worn out at 130,000 miles or so, depending on rear end oil changes.
The clutch is about the only place that comes to mind, that would cause slippage.
A quick test to see if the noise is coming from the rear end or not, is to siphon out (hot) a pint of diff oil and add a bottle of gear Moly. If things get significantly quieter, you know where to look.